/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.aliyuncs.auth;

import java.io.UnsupportedEncodingException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import com.aliyuncs.http.FormatType;
import com.aliyuncs.http.MethodType;
import com.aliyuncs.utils.ParameterHelper;

public class RpcSignatureComposer implements ISignatureComposer {

	private static ISignatureComposer composer = null;
	private final static String SEPARATOR = "&";
	
	private RpcSignatureComposer() {
		
	}
	
	public Map<String, String> refreshSignParameters(Map<String, String> parameters,
			ISigner signer, String accessKeyId, FormatType format) {
		Map<String, String> immutableMap = new HashMap<String, String>(parameters);
		immutableMap.put("Timestamp", ParameterHelper.getISO8601Time(null));
		immutableMap.put("SignatureMethod", signer.getSignerName());
		immutableMap.put("SignatureVersion",signer.getSignerVersion());
		immutableMap.put("SignatureNonce", ParameterHelper.getUniqueNonce());
		immutableMap.put("AccessKeyId", accessKeyId);
		if (null != format)
			immutableMap.put("Format", format.toString());
		return immutableMap;
	}

	public String composeStringToSign(MethodType method, String uriPattern,
			ISigner signer, Map<String, String> queries,
			Map<String, String> headers, Map<String, String> paths) {
		
		String[] sortedKeys = queries.keySet().toArray(new String[]{});
        Arrays.sort(sortedKeys);
        StringBuilder canonicalizedQueryString = new StringBuilder();
        try { 
	        for(String key : sortedKeys) {
	            canonicalizedQueryString.append("&")
	            .append(AcsURLEncoder.percentEncode(key)).append("=")
	            .append(AcsURLEncoder.percentEncode(queries.get(key)));
	        }
	
	        StringBuilder stringToSign = new StringBuilder();
	        stringToSign.append(method.toString());
	        stringToSign.append(SEPARATOR);
	        stringToSign.append(AcsURLEncoder.percentEncode("/"));
	        stringToSign.append(SEPARATOR);
	        stringToSign.append(AcsURLEncoder.percentEncode(
	                canonicalizedQueryString.toString().substring(1)));
	        
	        return stringToSign.toString();
        } catch (UnsupportedEncodingException exp) {
        	throw new RuntimeException("UTF-8 encoding is not supported.");
        }
        
	}
	
	public static ISignatureComposer getComposer() {
		if (null == composer)
			composer = new RpcSignatureComposer();
		return composer;
	}
}
